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Here you will find hardware documentation, installation instructions, and some examples of previous builds. Go take a look around!
- What is the CarPiHAT?
- Who might use a CarPiHAT?
- Where can I buy a CarPiHAT?
- How do I set up my CarPiHAT?
- What if I need more GPIO?
The CarPiHAT is a Raspberry Pi HAT, designed to make installing a Raspberry Pi in your car, boat, truck, or any other predominantly 12V system as painless as possible. The HAT conforms to the official Raspberry Pi specification, and is compatible with any Raspberry Pi with the 40 pin GPIO header, although it is primarily designed for use with non-zero variants.
Whilst shopping for a simple power supply and shutdown solution for my OpenAuto Pro installation, I was unable to find a solution that offered all of the features I was after in a single HAT. Unhappy with the concept of stacking multiple hats to achieve the result I was after, I decided to design my own, and thus, the CarPiHAT was born.
- 12V -> 5V buck converter to power the pi and touchscreen, with fuse and filtering.
- Safe shutdown circuitry to allow the pi to control its own power.
- < 1mA current draw when switched off.
- Dedicated reverse, illumination and aux 12V inputs.
- 2 general purpose 12V inputs. (for a total of 5 12V inputs)
- 2 high current, high side switched 12V outputs (@1A). (great for switching relays, lights ect)
- 1 independent CAN bus port.
- Real time clock to maintain system time across reboots.
- Broken out I2C bus.
- Broken out 1W for temperature sensor etc.
- 5V Power Output for display etc.
All 12V inputs are opto-isolated to ensure the Raspberry Pi is well protected against the typically noisy automotive power environment.
At a basic level, anyone who is looking to install a Raspberry Pi in their car, or other 12V system. Since the HAT allows the Raspberry Pi to take control of its own power supply, this means corrupted SD cards (due to unexpected power loss) are a thing of the past! A simple script, or service, running on the Pi allows you to monitor a 12V feed, and gracefully shut down when this is removed.
At a more advanced level, the additional peripherals on the HAT would allow you to connect any number of inputs or outputs to the system. The 12V outputs allow you to control lights, amplifiers, relays, solenoids, you name it! The CAN port allows the connection of an IDrive controller for a great human interface experience, or even interrogate your car's ECU with some custom software. The I2C and 1W ports allow you to connect any number of external devices such as light, temperature or environmental sensors, or even external microcontrollers!
In the past, people have installed HAT's in their cars, boats and trucks, as well as using them as simple, robust Raspberry Pi power supplies.
Currently, the best place to purchase a HAT is through the Pi Hut, based in the UK. They offer competitive international shipping, and even offer the optional cooling shrouds:
Please find the quick start guide here:
Please find documentation for the IO Expander here: